Fuel Oil for Ferries: From Too Dirty to Measure to ISO 16/14/11

The challenge

A ferry operator was concerned about the cleanliness of the fuel oil feeding its fleet, both as delivered by its supplier to the bunker barge and as delivered from the barge to the ferries. Independent lab analysis showed the delivered fuel at ISO 20/18/12, above both the ISO 4406 minimum and the engine manufacturer's recommended limit of 18/16/13, with 7,274 particles/mL at ≥4 µm against a limit of 2,500. The fuel in the bunker barge tank was worse: contamination inside the tank was mixing with the delivered fuel, and there was so much of it that the lab could not produce a meaningful reading. As part of a Delta-Xero fuel cleanliness assessment, a sample of the barge fuel was filtered and its condition independently monitored and verified.

Customer savings & impact

Following filtration with a Delta-Xero DX-1001-T-PT system fitted with an inline particle counter, the fuel showed clear, measurable improvements:

• Cleanliness improved from ISO 24/23/22 to 14/13/12 in just 25 minutes of filtering

• Independent lab verification at ISO 16/14/11, well within the engine manufacturer's 18/16/13 limit, with ≥4 µm particles down to 434/mL against a limit of 2,500

• Fuel returned from a critically contaminated state to well within ISO 4406 and engine manufacturer standards, supporting a longer mean time between failures, less downtime and lower O&M costs

The full case study shows how contamination levels fell during filtering, what ISO improvements were independently verified, and how continued filtration can clean the bunker barge tank itself, removing the need for tank flushing and eliminating diesel bug.